R&D on scintillation materials for novel ionizing radiation detectors for High Energy Physics, medical imaging and industrial applications

The Crystal Clear Collaboration (CCC) was approved by the Detector R&D Committee as RD18 in 1990 with the objective of developing new inorganic scintillators suitable for crystal electromagnetic calorimeters of LHC experiments. From 1990 to 1994, CCC made an intensive investigation for the quest of the most adequate ideal scintillator for the LHC; three main candidates were identified and extensively studied : CeF$_{3}$, PbWO$_{4}$ and heavy scintillating glasses. Lead tungstate was chosen by CMS and ALICE as the most cost effective crystal compliant to LHC conditions. Today 76648 PWO crystals are installed in CMS and 17920 in ALICE. After this success Crystal clear has continued its investigation on new scintillators and the understanding of scintillation mechanisms and light transfer properties in particular : The understanding of cerium ion as activator, The development of LuAP, LuYAP crystals for medical imaging applications, (CERN patent) Investigation of Ytterbium based scintillators for solar neutrinos spectroscopy and more recently on LuAG crystals. The Crystal clear Collaboration is currently involved in : The development of new crystal production methods: Micropulling down techniques, which allow growing monocrystals in form of fiber, which open attractive possibilities for the design of new detector. Ceramics Heavy scintillating glasses The study of cryogenic scintillators for dark matter searches and antimatter experiments Scintillating materials for beam diagnostics Generic studies to improve light production, light collection and timing characteristics … In the domain of inorganic scintillators, the Crystal Clear Collaboration is working in close collaboration with industrial partners and experts in crystal growing, solid state physics, defects in solids, optics, etc…. In 1992, the Crystal clear collaboration organised the 1$^{st}$ conference on the scintillator and their applications Crystal 2000) which since that time brings together experts and users of scintillating materials every 2 years under the brand of the SCINT conference, a major international event in the field of inorganic scintillating materials. In parallel to the crystal generic activity, in 1997 CCC decided to apply and transfer its expertise to fields where inorganic scintillators could make a significant impact to industry and society at large. CCC identified medical functional imaging and in particular Position Emission Tomography (PET) as most promising fields, due to its growing importance in cancer diagnostic, and to its similarities with HEP electromagnetic calorimetry. As a result, CCC members developed and constructed several dedicated PET prototypes: Small Animal PET (ClearPET™) machine for drug discovery. Five prototypes have been built inside the collaboration and this machine is now licensed to and commercialisedby industry (Raytest GmbH, Germany). A PET camera dedicated to breast imaging (ClearPEM) which is now entering the pre-clinical phase in Coimbra, Portugal. A second CLEARPEM machine has been built for the project ClearPEM-Sonic lead by CERIMED (www.cerimed.web.cern.ch) regrouping CCC members and non CCC members. This machine is installed since December 2010 in the North hospital in Marseille, France, for clinical evaluations. A PET for brain imaging : BrainPET, to be delivered in 2012 in Madrid, Spain. In addition members of CCC initiated the development of a dedicated Monte Carlo simulation software package GATE, a GEANT4 based simulation tool initially developed for the ClearPET project (http://www.opengatecollaboration.org/)). Currently, members of CCC are involved in several projects for the implementation of multimodality systems: PET-MRI PET- CT PET-US In summary, CCC is active in academic R&D on scintillating materials and on core R&D on novel ionizing radiation detecting devices, including readout electronics and data acquisition, for HEP and PET, SPECT (Single Photon Emission Computed Tomography) and on the development of medical imaging prototypes. Note : The rules and regulations for the activities of CCC are agreed by contract K1500/TT/PH/004C